JPH06170578A - Nozzle for laser cutting - Google Patents

Abstract

PURPOSE:To obtain a good cut surface having excellent smoothness by concentrically blowing an assist gas at and under a sufficiently high flow velocity and high dynamic pressure to the molten part of the cutting part and hardly generating the disorder of the flow of the assist gas. CONSTITUTION:A nozzle front end face 5 facing the front surface of a member W to be cut is provided in contact therewith or apart a slight spacing therefrom. A laser beam irradiation hole 11 is opened at this nozzle front end face 5 and an assist gas ejection port 15 is opened at the nozzle front end face 5. The opening shape of this assist gas ejection port 15 is formed to a slit shape meeting the cutting shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser cutting nozzle, and more particularly to a laser cutting nozzle used for laser cutting using an assist gas.

[0002]

2. Description of the Related Art In laser cutting, oxygen is added to a cutting portion in order to quickly remove the melted material of the cutting member melted by irradiating the cutting member with a laser beam.
Spraying an assist gas such as an inert gas has been conventionally performed.

Conventionally, in a laser cutting processing nozzle having a function of ejecting an assist gas, a laser beam irradiation hole and an assist gas ejection port are formed into one common circular cross-sectional shape, or a laser beam irradiation hole An assist gas ejection port is formed on the outside in an annular shape so as to surround the laser beam irradiation hole.

[0004]

The effect of removing the melted material of the member to be cut from the cut portion by the assist gas is that the assist gas is concentrated on the cut portion, particularly the portion melted by the laser beam irradiation, and has a high flow rate and a high flow rate. It is preferable that the assist gas is blown with a dynamic pressure, but in the conventional laser cutting nozzle as described above, the assist gas is concentrated in the melted portion of the cutting portion due to the cross-sectional shape of the assist gas ejection port, etc. , Not enough to be sprayed with high dynamic pressure.
Further, turbulence easily occurs in the flow of the assist gas blown to the assist gas melting portion, which hinders the smoothness of the cut surface.

The present invention has been made by paying attention to the above-mentioned problems in the conventional laser cutting nozzle, and the assist gas is concentrated in the molten portion of the cutting portion and has a sufficiently high flow rate. With the object of providing a laser cutting nozzle that can be sprayed at a high dynamic pressure, is less likely to cause turbulence in the flow of assist gas, and can obtain a good cut surface with excellent smoothness. There is.

[0006]

According to the present invention, the above-described object has a nozzle tip surface which is in contact with the surface of a member to be cut or which opposes at a slight interval, and a laser beam is provided on the nozzle tip surface. This is achieved by a nozzle for laser cutting which is characterized in that the irradiation hole is opened and the slit-shaped assist gas ejection port is opened.

In the laser cutting nozzle according to the present invention, the assist gas ejection port may be connected to a Laval nozzle so that the assist gas is supplied from the Laval nozzle.

Further, in the laser cutting nozzle according to the present invention, the assist gas ejection port may be formed with a slit width dimension substantially equal to a cutting lateral width dimension of the member to be cut by laser beam irradiation. .

[0009]

According to the above-mentioned structure, since the assist gas outlet is opened in a slit shape, the assist gas is sprayed to the melted portion of the cutting portion with a blade-shaped jet stream following the slit shape. To be

When the assist gas is supplied from the Laval nozzle to the assist gas jet, the assist gas flow is accelerated from subsonic to supersonic when passing through the Laval nozzle, and the assist gas is subsonic to supersonic from the assist gas jet. It is sprayed on the melting part of the cutting part.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2 show an embodiment of a laser cutting nozzle according to the present invention. In the figure, reference numeral 1
Shows a processing head of the laser cutting device, and the laser cutting processing nozzle 3 is attached to the tip portion of the processing head 1, that is, the lower end portion in the illustrated example.

The laser cutting nozzle 3 is a member W to be cut.
A nozzle body 7 having a flat nozzle tip surface 5 that is in contact with the surface of the nozzle or is opposed to the nozzle surface at an extremely small interval. 9 is formed. The laser beam passage 9 opens in the nozzle tip surface 5 as a laser beam irradiation hole 11 having a circular cross section, and a laser beam from a laser source (not shown) is focused by a condenser lens 13 attached to the processing head 1. Through the laser beam passage 9 and from the laser beam irradiation hole 11 to the member W to be cut.
Is irradiated on the surface of. In order to bring the laser cutting nozzle 3 into contact with the surface of the member W to be cut or to face it at a very small interval, for example, a labyrinth seal is formed on the lower end surface 5 of the nozzle.

In FIG. 1, the machining head 1 moves to the left relative to the member W to be cut (when the machining head 1 is fixed, the member W to be cut is moved to the right in the figure). A slit-shaped assist gas ejection port 15 is opened in the nozzle tip surface 5 of the nozzle body 7. The assist gas ejection port 15 extends in a straight line on a line passing through the central portion of the laser beam irradiation hole 11 and is open at one end to communicate with the laser beam irradiation hole 11. This assist gas outlet 15
The slit width dimension is set to a value that is substantially equal to the cutting lateral width dimension of the member W to be cut by laser beam irradiation. In addition, the length of the spout 15 (width in the left-right direction in the figure)
Is about 2 to 7 times the cut width dimension.

The nozzle body 7 is provided with a Laval nozzle 17 which inclines to the right as it goes upward in the figure. The Laval nozzle 17 is connected to the assist gas ejection port 15 on the outlet side. The Laval nozzle 17 is a fine nozzle for subsonic to supersonic injection having a throat 19 in the middle portion, and is an inert gas such as argon gas or nitrogen gas or oxygen gas supplied from the assist gas source to the inlet portion 21. The subsonic to supersonic injection is performed to the assist gas ejection port 15 toward the assist gas ejection port 15. In this case, since the laval nozzle 17 is inclined rightward in FIG. 1, the gas flow reaches the cutting portion near the lower surface of the member W to be cut at high speed.

The laval nozzle 7 is formed so that its cross section is rectangular (that is, the lateral wall of the nozzle is a plane wall parallel to the plane of FIG. 1) and its lateral width (that is, the plane of the plane). The space between the parallel walls is formed to be the same as the slit width of the ejection port 15.

The jet port 15 and the laval nozzle 17
The tip of the upper wall may end in front of the laser beam, as indicated by the chain double-dashed line 50 in FIG. As a result, the gas flow can be jetted perpendicularly to the plane of the member W to be cut.

According to the above-mentioned structure, the surface of the member W to be cut is irradiated with the laser beam from the laser beam irradiation hole 11, whereby the member W to be cut is melted. When the assist gas passes through the Laval nozzle 17, the assist gas is accelerated to a subsonic speed to a supersonic speed, and the assist gas ejection port 15 follows the slit shape thereof to form a blade shape having a lateral width dimension substantially equal to the cutting lateral width dimension of the member W to be cut. Is jetted intensively to the molten portion of the member W to be cut at a high flow velocity of subsonic speed to supersonic speed.

Since this assist gas forms a blade-shaped jet having a lateral width substantially equal to the cutting lateral width of the member W to be cut, this assist gas produces a jet that matches the slit shape due to the cutting of the member W to be cut. None, at a sufficiently high flow velocity and high dynamic pressure of subsonic to supersonic speed, the melted material of the member W to be cut is efficiently blown off and removed from the cut portion without being disturbed in the flow and is sprayed to the cut portion without waste. .

As a result, the melted material of the member W to be cut is blown off satisfactorily and a cut surface having excellent smoothness is obtained.

Further, since the nozzle tip surface 5 of the assist gas ejection port 15 is in contact with the surface of the member to be cut W or is opposed to the surface of the member to be cut W at a minute interval, the nozzle tip and the member W to be cut W.
In between, a sealing property is obtained in which the assist gas does not escape along the surface of the member W to be cut, and this also allows the assist gas to be blown to the cut portion without waste. Further, as a result, the gas flow is uniquely supplied to the cutting groove, and turbulent flow or the like is prevented from occurring at the cutting portion.

Although the gas inlet 21 is opened in the lateral direction in the drawing, it may be opened in the upward direction. As a result, the rectifying property of the gas flow at the ejection port 15 is further improved.

Further, the nozzle body 7 can be provided on the machining head 1 so as to be rotatable around the laser beam. Thereby, the direction of the laval nozzle 17 can be changed according to the variation of the cutting direction.

FIGS. 3 and 4 show another embodiment of the laser cutting nozzle according to the present invention. Incidentally, FIG. 4, parts corresponding to those in FIGS. 1 and 2 are indicated by the same reference numerals as those in FIGS. 1 and 2. In this embodiment, the assist gas is supplied into the laser beam passage 9 through the inlet portion 21, the Laval nozzle 17 is formed in the laser beam irradiation hole 11 portion, and the laser beam irradiation hole 11 is traversed in a straight line. A slit-shaped assist gas ejection port 15 is formed. The slit width dimension of the assist gas ejection port 15 is also set to a value substantially equal to the lateral cutting width dimension of the member W to be cut by laser beam irradiation.

Also in this embodiment, the surface of the member W to be cut is irradiated with the laser beam from the laser beam irradiation hole 11, whereby the member W to be cut is melted and the assist gas passes through the Laval nozzle 17. The subsonic-supersonic velocity is accelerated from the subsonic speed to the supersonic speed, and a blade-shaped jet having a width dimension substantially equal to the cutting lateral width dimension of the member W to be cut is imitated from the assist gas ejection port 15 following the slit shape thereof. The melted portion of the member W to be cut is intensively sprayed at a flow velocity.

Therefore, also in this embodiment, the same effect as the above-mentioned embodiment can be obtained.

In the above, the present invention has been described in detail with respect to specific embodiments, but the present invention is not limited to these, and various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

[0028]

As can be understood from the above description, in the laser cutting processing nozzle according to the present invention, the assist gas is formed in a slit shape because the assist gas ejection port is opened in a slit shape. A blade-like jet is intensively sprayed on the molten part of the cutting part, and the assist gas flow is accelerated from the Laval nozzle to subsonic to supersonic speed, and the assist gas is cut from the assist gas jet at subsonic to supersonic speed. Since the assist gas is sprayed on the molten part of the cutting part, the assist gas can be sprayed intensively on the molten part of the cutting part with sufficient high flow velocity and high dynamic pressure without waste and without disturbing the flow. It becomes possible to efficiently perform laser cutting processing by a cut surface having excellent smoothness.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a laser cutting nozzle according to the present invention.

FIG. 2 is a bottom view of the laser cutting nozzle according to the present invention shown in FIG.

FIG. 3 is a vertical cross-sectional view showing another embodiment of the laser cutting nozzle according to the present invention.

4 is a bottom view of the laser cutting nozzle according to the present invention shown in FIG. 3. FIG.

[Explanation of symbols]

 1 Processing Head 3 Laser Cutting Processing Nozzle 5 Nozzle Tip Surface 7 Nozzle Body 9 Laser Beam Passage 11 Laser Beam Irradiation Hole 13 Condensing Lens 15 Assist Gas Jet 17 Laval Nozzle 19 Throat 21 Inlet

Claims (3)

[Claims] 1. An assist gas ejection port having a nozzle tip surface which is in contact with a surface of a member to be cut or which opposes at a very small interval, and a laser beam irradiation hole is opened in the nozzle tip surface and which has a slit shape. Nozzle for laser cutting processing characterized by having an opening. 2. The nozzle for laser cutting according to claim 1, wherein the assist gas ejection port is connected to a Laval nozzle, and assist gas is supplied from the Laval nozzle. 3. The assist gas ejection port is formed with a slit width dimension substantially equal to a cutting lateral width dimension of the member to be cut by laser beam irradiation. Laser cutting nozzle.